In color papers there is a need for providing color papers with improved resistance to the transmission of water vapor. Present color papers are coated with a photosensitive layer(s) containing dye couplers as well as hardeners that are required to react with the gelatin to impart physical properties to control the amount of layer swelling when rewet during processing and also a degree of physical toughness to resist scratching and allow the emulsion coated paper to be slit and cut in a reasonable time. This process can be time dependent as well as sensitive to the amount of moisture in the dried emulsion and the paper base. The current photographic base has a certain propensity to allow water vapor to pass between the paper base and the emulsion layer. The rate at which this exchange occurs has an impact on the rate and ultimate hardness of the emulsion coated layer. There remains a need to reduce the water vapor transmission between the emulsion and the paper base to provide for improved hardness and improved scratch resistances. Paper by nature will absorb or give off moisture as it is exposed to varying humidity conditions. Since photographic paper has slit edges that expose paper that is not covered by a layer of polyethylene, there is a tendency for the edges of the photographic support to either gain or lose moisture at a rate that is different than the center of the web. This process creates a differential moisture profile from the edge to the center of the web. This moisture difference can then cause a difference in the response of the photosensitive components. There remains a need to reduce the moisture exchange between the emulsion and the paper base. By reducing the rate or eliminating the loss of moisture from the emulsion through the current polyethylene layer into the paper base that there will be less variation in the photographic response. Melt extruded cast polyethylene used in photographic paper has a water vapor transmission rate of at about 1.6.times.10.sup.-5 g/mm.sup.2 /day. There remains a need for a layer between the silver halide emulsion and the paper base that has a higher resistance to the flow of water vapor from the emulsion to the paper base. There also remains a need for a layer on the backside of an emulsion coated paper base to have a high resistance to the flow of water vapor. This is important during manufacturing and photographic processing when the photographic element is in wound roll form. The photographic emulsion is between the the emulsion said and back side layers. This creates a sandwich effect on each side and allows the moisture to remain in the emulsion longer which is critical to assure hardening. There also remains a need to improve the transient core set curl of photographic paper. By reducing the water vapor transmission properties of the photographic paper an improvement can be made.
In U.S. Pat. No. 4,283,486 a mechanism to the control the oxygen flow rate through the paper base to reduce image dye discoloration was discussed. In U.S. Pat. No. 4,581,267 a method to over laminate a photographic print to protect against moisture is disclosed. A method to control the rate of water vapor transmission in packaging applications using biaxially oriented multiple layer sheets is disclosed in U.S. Pat. No. 5,543,223 and U.S. Pat. No. 5,192,620, the disclosure of which is incorporated by reference.